An automatic stop-and-start device of an engine is used as an idling stop-and start system (ISS) of a vehicle and automatically stops the engine when a predetermined stop condition is fulfilled and automatically starts the engine when a predetermined start condition is fulfilled (see, for example, Japanese Patent Application Laid-Open No. 2003-260960). With such an automatic stop-and-start device, by automatically stopping the engine in an idling state such as during stopping and parking of vehicle, and automatically starting (restarting) the engine when the vehicle is started, it is possible to lower fuel consumption and reduce the generation of exhaust gas and noise.